Telecommunications has become a major part of everyday life in modern society, allowing people to directly communicate with one another regardless of current location and to leave voicemails when a called party is busy on another call or is otherwise unavailable to answer. An important service to many customers is the ability to have an incoming call cause two or more phones to ring, with the call being connected to the first phone to answer. One example includes device extensions within homes or offices, where each land-line phone will ring to indicate an incoming call. When an answering party picks up one of the phones, the call is delivered to the answered phone, and all the phones stop ringing. In this service, moreover, additional parties may join the call after the initial call delivery by simply picking up their extension. Wireless systems provide so-called flexible alerting (FLEX ALERT) services that are intended to provide somewhat similar functionality, wherein each member of a predefined group (e.g., flexible alerting group) of directory numbers (DNs) is alerted when a call comes in to an associated primary directory number. In conventional flexible alerting implementations, a mobile switching center (MSC) receives the incoming call to a pilot or primary DN and fans the call out to a plurality of call legs (e.g., directs the incoming call to the multiple different mobile or wireline secondary DNs of the predefined alerting group), and whichever outgoing call leg is the first to answer will receive the call, with the remaining legs being released. IP-based telephony systems also provide generally equivalent multiple call leg functionality, sometimes referred to as Simultaneous Ringing (SIM RING) services. Moreover, such multiple call leg services are available across groups including multiple technology type devices, wherein an alerting group may be comprised of land-line phones, wireless phones, and/or IP-based phones.
As can be appreciated, it may be desirable in all the above variants of the multiple call leg type services to provision the multiple call legs such that the end point devices ideally ring or otherwise alert the user at approximately the same time. For instance, the predefined group of secondary DNs may correspond to members of a sales force, where each group member is ideally given an equal chance of receiving the incoming call. However, if the call processing time for some member devices is different than others and the individual call legs are sent out at the same time, a first member phone may in some cases ring several times before another device rings once. As a result, the call may be answered by one member before another member (associated with long processing delays) even hears a ring, and thus certain member devices associated with the longest delays relative to the primary DN may never be given the opportunity to answer the incoming call. To address these circumstances, certain approaches provide for sending out the different call legs at different times in order to attempt to compensate for different delays in the different legs, wherein a home location register provides delay parameters for each member DN in a given group, and these are used to determine when each leg will be initiated by the MSC. In the conventional implementations, however, the rings are generally delayed by static amounts, and the service does not account for dynamic changes that could cause the rings to be skewed in time. Further complicating the situation is the possibility that one or more member DNs may be connected to (or subscribed to) ancillary answering or forwarding mechanisms or services. For instance, answering machines or voicemail services may be associated with a particular member phone, which can be configured to pickup immediately or after a predetermined number of rings. Also, call forwarding services may be enabled for a given member, which forward an incoming call to the member DN to another location, and the forwarding may be programmed to occur immediately, or after a certain number of rings, etc. In view of these and other conditions and possible configuration variations in the group member devices, the conventional approaches to multiple call leg situations cannot ensure that the members are alerted at the same time, particularly as conditions change, whereby there is a continuing need for improved methods and systems for processing multiple leg calls.